19056: Input request content type is invalid

This error is returned when an API request's Content-Type header is not one of the formats Twilio APIs accept for requests, causing Twilio to reject the payload. Twilio's error entry lists this as "Input request content type is invalid," and Twilio documents that API requests must use application/x-www-form-urlencoded or multipart/form-data.

• The request was sent with application/json instead of application/x-www-form-urlencoded or multipart/form-data required for Twilio REST API requests. Some endpoints explicitly document application/x-www-form-urlencoded as the encoding type.
• The body encoding does not match the declared Content-Type header (for example, JSON data while declaring application/x-www-form-urlencoded). Twilio guidance emphasizes that body content must align with the declared content type.
• An endpoint that expects file uploads was called without providing the appropriate Content-Type and payload format (for example, media upload workflows that require setting Content-Type to the file's MIME type and sending the file content accordingly).

• Set the Content-Type header to an accepted type for Twilio API requests—application/x-www-form-urlencoded or multipart/form-data—and ensure the payload is encoded to match.
• Check the specific endpoint's API reference for its required encoding and adjust your request accordingly (for example, some Messaging resources state "Encoding type: application/x-www-form-urlencoded").
• For media or file-upload endpoints, set Content-Type to the correct MIME type and send the payload in the documented format (e.g., binary body when instructed).

• Twilio API requests
• Services resource
• Webhooks security